In order to meet the needs of modern social life and living environment, people need larger coverage spaces, such as large venues, gymnasium roof, prefab hangar, exhibition halls and waiting rooms. The span requirements of these buildings are getting larger and larger, tens of meters or even larger. The roof system that meets this long-span requirement can only be a spatial structure, so the spatial structure has become a structural form that has attracted much attention. The space structure has the advantages of reasonable force, light total amount, low cost, lively and novel form, and can highlight human artistic creativity. It can make full use of the characteristics of different materials to meet the needs of various changing architectural shapes. However, the space structure has a three-dimensional structure and is subjected to three-dimensional force under the action of the load, and the structural forming and force analysis are extremely complicated. In recent years, the popularization of computers has made long-span spatial structures develop at an extraordinary speed, which has had a significant impact on modern architecture.
Among the many forms of space frame structure, the space frame structure has developed the most rapidly. It is a spatial rod structure formed by arranging the rods according to certain rules and connecting them through nodes. Its shape can be flat, that is, space frame, or it can be a curved surface, that is, space shell. Among them, the space frame is the most widely used at home and abroad. The space frame members mainly bear the action of axial force, and the cross-sectional size of the members is relatively small, and the rod members where these spaces intersect support each other, which organically combines the force-bearing members and the supporting system, so the material is economical. Due to the strong regularity of structural combination, the shape and size of rods and nodes are the same, which is convenient for factory production and site installation. The space frame structure is generally a high-order statically indeterminate structure, which has a high safety reserve, can better withstand concentrated loads, dynamic loads and asymmetric loads, and has good seismic performance. The space frame structure can adapt to the requirements of public buildings and industrial workshops with different spans and different supporting conditions, as well as different building planes and their combinations. The biggest advantage of the space frame structure is reflected in the large and medium-span roof structure. At this time, the use of the space frame is more economical and reasonable than the portal rigid frame and the steel roof truss.
The space frame structure is a higher statically indeterminate structure that composed of many rods regularly from two directions or several directions. It changes the stress system of the general plane truss and can bear loads from all directions. The biggest feature of the space frame structure is that due to the mutual support between the rods, the rigidity is large, the integrity is good, the earthquake resistance is strong, and it can withstand the adverse effects caused by the uneven settlement of the foundation; even if the individual rods are damaged. It can also automatically adjust the internal force of the rod to maintain the safety of the structure.
The amount of steel used for the space frame steel structure building is less, and the steel consumption of the steel pipe space frame with a span of 18m is only 7~10kg/m2. The steel consumption of a 112m span angle steel frame is only 65kg/m2. The height of the space frame structure is small, and the structural space can be effectively used as the building space. The space frame structure has great adaptability and is suitable for both small and medium-span buildings as well as large-span houses. In terms of building plane form, the space frame structure can also be adapted to buildings in various plane forms: such as rectangular, circular Shaped, fan-shaped and various polygonal plane building forms.
The space frame structure is convenient to obtain materials. Generally, Q235 steel or 16Mn steel is used. The cross-section of the rod is mostly steel pipe or section steel (the section steel is mainly angle steel), and large-span buildings can be built with small-sized rod sections. In addition, the space frame structure is suitable for factory production due to its uniform rod specifications, which provides favorable conditions and guarantees for accelerating the progress of the project. The space frame structure can be analyzed by a general calculation program, the drawing is simple, and the characteristics and advantages of the space frame itself provide favorable conditions for the development of the space frame structure.
